Iraq's parliament called for the government to draw up a timetable for the withdrawal of foreign troops from the country in a resolution passed on Thursday, the speaker's office said.

"The Iraqi parliament expresses its gratitude to all countries which have supported Iraq in its fight against Daesh (the Islamic State group) and calls for the government to draw up a timetable for the withdrawal of foreign troops," it said in a statement.

Washington in October 2014 forged a 74-country coalition to assist Iraqi forces in a fightback against IS which had seized swathes of the country and posed a military threat to Baghdad.

On February 5, the coalition announced it was "adjusting" its force levels in Iraq downward as it shifted away from combat operations following the jihadists' expulsion from all Iraqi urban centres.

Brigadier General Jonathan Braga, the coalition's director of operations, said "an appropriate amount of capabilities" would be kept in Iraq in addition to the forces needed to train, advise and equip the Iraqis.

Such a presence would be coordinated with the Iraqi government, said the coalition, whose main force is made up of 5,000 US soldiers in Iraq.

US forces occupied Iraq for eight years, between a 2003 invasion that toppled dictator Saddam Hussein and their withdrawal in December 2011. Three years later, IS seized a third of Iraq, sweeping aside security forces.

On Tuesday, Iraqi Prime Minister Haider al-Abadi said that coalition force numbers were now "very limited" and stressed it was "out of the question to give them a base on our territory".

"There is no base or airport controlled by foreign forces... No aircraft lands or takes off without our authorisation," he told a news conference.

In October, the prime minister strongly defended the Hashed al-Shaabi, an umbrella group dominated by Iran-backed Shiite militias, after comments from US Secretary of State Rex Tillerson that foreign fighters and Iranian militias in Iraq should "go home".

Abadi said they were Iraqi volunteer fighters who had played a major role in the military defeat of IS.